The headword, presumably extracted from the quotation given, is present participle, masculine nominative singular, of the verb u(pospani/zw.
[1] An approximation of Procopius, Secret History 19.5 (web address 1); cf. Kaldellis (87). In the source text the verb form is lhi/+zhtai, the third person singular, present middle-passive subjunctive: "he might start robbing his subjects". Procopius here describes the emperor Anastasios's (cf. alpha 2077 generally) concerns about a successor caught in a future financial pinch.